Agner Fog, Intel Developer Forum, AVX-512 is a big step forward – but repeating past mistakes! here.
AVX512 is arguably the biggest step yet in the evolution of the x86 instruction set in terms of new instructions, new registers and new features. The first try was the Knights Corner instruction set. It had some problems and AVX512 is better, so I am quite happy that AVX512 seems to be replacing the Knights Corner instruction set. But there are still some shortsighted issues that are lilkely to cause problems for later extensions.